My 1993 3.0 has recently developed a knocking noise in the front, but only with braking, and sharp cornering at slow speeds. I replaced the sway bar links and bushings hoping that would cure it, but no. I've read several posts about upper control arm bushings, and that sounds scary. What about tie-rod ends? Could it be those, and how difficult (and expensive) are they to replace myself? I need to change the rack, so if it's the tie-rod ends, I'll do it all together. I'm just curious about the cost, and time I should expect to spend doing it.

 

My 96 Aero did this recently it turned out to be the tie-rods to test them jack the car up with a floor jack. Grab one of the front tires with your two hands one on the left and another on the right of the tire and try to shake the tire if there is noticable play then your tie rods are shot.

My vehicles tie-rods were so bad you could hear the quiet knocking when driving straight.

They're not that difficult to replace just make sure you have a jaw puller to pull the tie-rod end from the spindle arm the rest is pretty straight forward also be sure to have an alignment done after you install the new ones auto shops do this pretty inexpensively. Since the equipment for alignments is so expensive this is one of the only things I leave to a shop.

 

If it's not the tie rods, what else should I look at? How would I check the upper control arm bushings? Just visually check the rubber?

 

I'd check for cracking, hardened, or missing bushings.

 

Thanks for the tips. I'll check it out as soon as I can.

 

CharlestonSC,
Loose shock mountings or broken shocks will make a knocking sound as will worn out wheel bearings. Look at those items first. While rare, the outer steel jacket of a shock absorber can break at the small, topside weld and bang around loudly. Grabbing one and trying to move it would confirm this. Threre are also instances where the inner shock plunger rod breaks and produces a knock during suspension travel. Wheel bearings can be tested for side-to-side play wth the wheel raised. There should be none. As previously noted, tie rod ends can be a culprit. If none of those provide clear evidence, then consider the upper ball joint.

Testing the upper control arm ball joint is not that "scary" if you have a floor jack or even a good scissors jack. The upper ball joint is a known problem area for Aerostars. To really test it, you need to loosen the wheel nuts, put a jack under the lower control arm and raise that side. Remove the wheel and place a jackstand for safety. Leave the jack in place and remove the pinch bolt on the upper spindle (just below the upper arm ball joint.) Once this bolt is out, push upward or if stuck, strike upwards with a rubber mallet to separate the upper joint from the spindle. You can now see the lower arm of the upper ball joint. Move this around and try to it push upwards into the body of the ball joint. The stub arm should show a moderate amount of resistance to movement in any direction. Any play from side-to-side and especially upwards is a sign of a worn ball joint. Very few last beyond 100,000 miles and some fail sooner depending on the type of road surfaces driven on.

 

I've replaced the swaybar links, rack, and tierod ends. I found out the hard way that you are supposed to KEEP the old jam nuts from the tierods. Where do I get new jamnuts?! HomeDepot doesn't carry them, and AutoZone doesn't carry them. I spoke with a Ford Dealership and was told they are 14mm with a 1.5 pitch. What does that mean? Will it be expensive to get them from Ford? I guess I should've asked while I had the guy on the phone. oops.

Also, there is still a considerable knock in the front. I'm pretty sure it's just on the passenger side. It knocks when braking, and also when turning the wheel from right to left. If I turn the wheel right, then back to left, it knocks. It even does it sitting in neutral. Would that be balljoints? How hard are they to replace?
Thanks! You guys are lifesavers!

 

My Aerostar does that knocking sound on sharp right turns and upon stops. It comes from the driver's side.
So far, I have replaced: both shocks, upper ball joints and sway bar bushings. Still knocking. The tie rod ends have been tested at the state inspection in November, they are ok. My next job are the lower ball joints. I will change them (hopefully) soon and see whether they were the problem.